This invention relates to a block and peg combination for the individual blocks of a modular wall construction. More particularly, cast blocks of cementations material accommodate pegs within holes configured at the bottom of the blocks to enable protruding conical heads of the pegs to be gathered to underlying V-shaped grooves for keying overlying courses of blocks to underlying courses of like blocks.
Blocks for the construction of relatively low (on the order of 4-foot) landscape retaining walls are known. Typically, these blocks are formed from cast cementatious material. They typically have a front face, a rear face, and two sides with each side extending between an edge of the front face and an edge of the rear face of the blocks. The blocks when viewed in plan have a trapezoidal shape with the front portion of the blocks constituting a wide dimension and the rear portion of the blocks constituting a narrower portion.
In forming such low walls, the walls are commonly laid in two dispositions. First, the walls can be vertical. Second, the walls can be canted, typically in a direction where the wall leans into the soil which the wall reinforces. In either case, the weight of the masonry of the wall is utilized to reinforce the soil behind the wall, which soil is typically for a garden bed, such as a flower bed.
It is required that such blocks key to one another. There are existing wall systems that utilize knobs on their bottom surfaces to key the course beneath, but these knobs are all integral sections of the wall units. Making knobs in this way has a low material cost compared with pins, and it also has the simplicity and reliability derived from the lack of any additional keying parts. On the negative side, however, making integral-bottom knobs is a more difficult procedure than making flat-bottomed units, and they are also more difficult to package and transport. Such blocks with integral knobs do not stack neatly for storage or shipment.
Various other schemes for keying such blocks are known. For example, in Blomquist et al. U.S. Pat. No. 6,488,448 and in Castonguary et al. U.S. Pat. No. 6,109,906, blocks are shown keyed to one another. These blocks include through holes or grooves in the blocks for accommodating interlocking pegs. The interlocking pegs register to underlying holes or grooves of the blocks to key an overlying course of such blocks to an underlying course of blocks.
Keying schemes to date have not been without disadvantage. Specifically, in some systems, at the time the blocks are keyed with respect to one another, the interlocking pins must be placed and manipulated through the holes of the overlying blocks. At the same time this manipulation occurs, the overlying block must be moved relative to the underlying block. During this relative movement between the respective overlying and underlying blocks, the pin must be manipulated to effectively “feel” for the desired registration between the respective blocks.
There are other known keying schemes. For example in one type of modular wall construction, it is known to place interconnecting pegs at the top of a first course of blocks forming the underlying layer of a modular block wall. Keying elements are then registered to upwardly concave holes within the second course of blocks as it is laid. Registration of holes at the bottom of the second course of blocks to the placed keying elements of the first course of blocks must occur. This registration is complicated. As the blocks approach one another for the desired registration, the view of the mason placing the blocks is obstructed. Typically, the mason simultaneously leans over to observe the required registration while at the same time trying to lower the block. Strain on the mason results. Further, in these keying schemes, pegs with eccentric protrusions are utilized. While such pins key the respective layers one to another, the eccentric nature of the keying part of the pin with respect to the groove can cause peg head shearing during installation. In such shearing, the eccentric cap of the pin is separated from the embedded shaft by torque exerted on the pin during masonry installation as the relatively heavy blocks are moved, one with respect to the other.